Offshore structures, such as those used by the petroleum industry, are sometimes moored to the seafloor using pile anchors. Existing pile anchors may generally be described as a single tubular element, typically circular in cross section, with a closed top and an open bottom. The ability of a pile anchor to moor an object is typically referred to as an anchor's “holding capacity.” In general, the holding capacity of a pile anchor increases with the size of the anchor. However, typically as the size of the anchor increases, so does the anchor's material, fabrication and installation costs. Additional background can be found in U.S. Pat. No. 5,915,326 to Karal, G B U.S. Pat. No. 1,269,599 A to Joppa et al., U.S. Pat. No. 5,704,732 to Horton, and U.S. Pat. No. 4,619,218 to Kenny. What is needed is a pile anchor installation system that reduces the high costs of material, fabrication and installation without substantially reducing the anchor's holding capacity.
There is also a need in the industry for a pile anchor that can maintain its holding capacity at a reduced size, or alternatively, that has an increased holding capacity for a given size. By increasing a pile anchor's holding capacity, one may be able to reduce the total number of pile anchors required to moor a floating structure. Decreasing the number of pile anchors reduces the material costs and installation time, which can be a significant cost component of offshore construction. The present invention may satisfy these needs.